[Newbies] Project on squeak language

Mon Aug 22 18:54:22 UTC 2016

From: roger mpouma
Sent: Monday, August 22, 2016 2:42 PM

Hi Ron,

I solved my problem, thank you for your help.

I got one more question, how can i add the possibility to erase parts of what i have already drawn as item "clear" but just parts of the drawing ? 

[Ron Teitelbaum] Of course everything is possible.  Your clear is doing just that, it’s filling in the canvas area with your background color.  There are number of ways to accomplish this.  A number of programs hold onto the results of each drawing collection (clicking and moving until you let go of the mouse) as a single element of the drawing.  Then you can ctrl –z to remove them in order.  To do something like that you need an instance of a class, something like Drawing, which holds a collection of brush strokes, colors and line widths,  and a collection on your canvas to apply the drawings in order to your canvas. An instance variable called drawings would work.   You could also calculate the intersection of a line and the position of the mouse pointer in the drawing to find each draw element and remove them when clicked.  You could also erase by simply overlaying the background color as another draw element, in other words, drawing a line with the background color on top of everything else is similar to erasing. 

Everything is possible!

All the best,

Ron Teitelbaum

2016-08-22 18:45 GMT+02:00 Ron Teitelbaum <ron at usmedrec.com>:

Hi Roger!  

That was a nice try!

I modified methods:

addCustomMenuItems: aCustomMenu hand: aHandMorph
    super addCustomMenuItems: aCustomMenu hand:  aHandMorph.
    aCustomMenu add: 'clear' action: #clear.
    drawColor := Color red.                    //modification
    drawColor := Color yellow.                //modification
    drawColor := Color green.                 //modification
    drawColor := Color blue.                   //modification

[Ron Teitelbaum]

What this does is create a menu with one item clear and then it sets the drawColor to red yellow green and then blue.  Since blue is the last color you end up with blue.

Try creating drawRed, drawYellow, drawGreen, and drawBlue methods

For example

drawRed

               drawColor := Color red.

Now add to your menu properly.

aCustomMenu add: 'clear' action: #clear.
aCustomMenu add: 'red' action: #drawRed.

Where add is what you see in your menu and action is what happens when you select the menu item.  (it calls: self drawRed)

Do that with all your colors and you should be all set!

You can also add menu items to adjust the size of the brush.  Maybe make small brush, medium brush and large brush menu items?  Works the same way as changing color.  You need a brushSize instance variable. And initialize brushSize := 2.

All the best,

Ron Teitelbaum

initialize
    super initialize.
    self extent: 500 at 700.
    drawColor := Color black.

mouseDown: evt
    brush := Pen newOnForm: form.
    brush roundNib: 2.
    brush color: drawColor.                                    //modification
    lastMouse := evt cursorPoint - bounds origin.
    brush drawFrom: lastMouse to: lastMouse.
    self invalidRect:
    ((lastMouse - brush sourceForm extent corner:
    lastMouse + brush sourceForm extent)
    translateBy: bounds origin).

The initial color is black.

When i click the command "change color" on the menu  and i chose for example the green color, the result is the blue color. I don't understand why ?

And after the first choice, i must restart the program with the Workspace for change another color. So i can't make several choices at the same time.

How can I solve these problems ? and to change size of the brush ? 

Thank you in advance.

2016-08-21 3:14 GMT+02:00 Ron Teitelbaum <ron at usmedrec.com>:

From: roger mpouma
Sent: Saturday, August 20, 2016 2:42 PM

How can i make  this please ?

I thought to add "color" and "size" commands as "clear" command in the custom menu code. After that, add "color" and "size" methods...

[Ron Teitelbaum] 

What I was thinking is making buttons on the panel. Color buttons with a highlight around it so you can see what is selected.  You could instead add something like Red or Blue to the menu.

On your class add some instance variable called drawColor or something like that.

When the menu item Red is called you would do 

drawColor := Color red.

Then in mouseDown:

    brush color: drawColor.

Initialize your color to something like black

Initialize

               drawColor := Color black.

So that the user is not required to use the menu to get the default color (black).

Hope that helps,

Ron

2016-08-20 20:26 GMT+02:00 Ron Teitelbaum <ron at usmedrec.com>:

Have you considered having a menu bar with colors and line sizes.  The users can select the color and line size which will change your program to use those settings.

All the best,

Ron Teitelbaum

From: beginners-bounces at lists.squeakfoundation.org [mailto:beginners-bounces at lists.squeakfoundation.org] On Behalf Of roger mpouma
Sent: Saturday, August 20, 2016 1:51 PM
To: A friendly place to get answers to even the most basic questions about Squeak.
Subject: Re: [Newbies] Project on squeak language

I have already implemented the canvas on which we draw, the possibility of drawing with the brush but with only a single color and a single size, a capacity to erase what we have already drawn with the "Clear" command on the custom menu code. 
So, i'd like to add the possibility of changing the color and the size of the brush presenting the choices of color and brush size.

The differents methods are:

"Methods"

extent: aPoint
    | newForm |
    super extent: aPoint.
    newForm := Form extent: self extent depth: 16.
    newForm fillColor: Color veryLightGray.
    form ifNotNil: [form displayOn: newForm].
    form := newForm.

initialize
    super initialize.
    self extent: 500 at 350.

drawOn: aCanvas
    aCanvas image: form at: bounds origin.

handlesMouseDown: evt
    ^ true     

mouseDown: evt
    brush := Pen newOnForm: form.
    brush roundNib: 3.
    brush color: Color red.
    lastMouse := evt cursorPoint - bounds origin.
    brush drawFrom: lastMouse to: lastMouse.
    self invalidRect:
    ((lastMouse - brush sourceForm extent corner:
    lastMouse + brush sourceForm extent)
    translateBy: bounds origin).

mouseMove: evt
    | p |
    p := evt cursorPoint - bounds origin.
    p = lastMouse ifTrue: [^ self].
     brush drawFrom: lastMouse to: p.
    self invalidRect: ((
        ((lastMouse min: p) - brush sourceForm extent) corner:
        ((lastMouse max: p) + brush sourceForm extent))
            translateBy: bounds origin).
    lastMouse := p.

addCustomMenuItems: aCustomMenu hand: aHandMorph
    super addCustomMenuItems: aCustomMenu hand: aHandMorph.
    aCustomMenu add: 'clear' action: #clear.

clear
    form fillColor: Color veryLightGray.
    self changed.

"Class PaintMorph"

Morph subclass: #PaintMorph
    instanceVariableNames: 'form brush lastMouse'
    classVariableNames: ''
    poolDictionaries: ''
    category: 'Morphic-Fun'

"Workspace"
PaintMorph new openInWorld.

Thank you in advance.

2016-08-20 18:47 GMT+02:00 Bert Freudenberg <bert at freudenbergs.de>:

Sure. Just ask some specific questions - e.g. what you tried, what worked, what didn't etc.

- Bert -

On Sat, Aug 20, 2016 at 10:59 AM, roger mpouma <rmpouma at gmail.com> wrote:

Hello, 
I need help for a drawing project on Squeak. I'd like implement a canvas on which we draw with the possibility of drawing with brush changing the color and size of the brush. Is it possibile to have help ?

Thank you in advance. 

_______________________________________________
Beginners mailing list
Beginners at lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners

_______________________________________________
Beginners mailing list
Beginners at lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners

_______________________________________________
Beginners mailing list
Beginners at lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners

_______________________________________________
Beginners mailing list
Beginners at lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners

_______________________________________________
Beginners mailing list
Beginners at lists.squeakfoundation.org
http://lists.squeakfoundation.org/mailman/listinfo/beginners

-------------- next part --------------
An HTML attachment was scrubbed...
URL: http://lists.squeakfoundation.org/pipermail/beginners/attachments/20160822/de17e070/attachment-0001.htm